Control system and device for dynamoelectric machines



NOV- 27,1951 w. R. HOLMES 2,576,117

CONTROL SYSTEM AND DEVICE FOR DYNAMOELECTRIC MACHINES Filed oct. 1o, 1945 2 swims- SHEET 1 5% l IIJ I IIJ -l M R b of, l n 1|. l. |l. wDH/. o@ m5 9 VM m/n /I mvwmvm (Esa. Y B

, WD@ MSTEMZ ATTOR N EY W. R. HOLMES Nov., 27', 1951 2 SHEETS-SHEET 2 Filed OGC. lO, 1945 mm. w//f/ W. m, R mw WH. w MVN --1 W lN/ ww m Q Q. W

A lmlllhllllllm NEN ATTOR N EY Patented Nov. 27, 1951 CONTROL SYSTEM AND DEVICE FOR DYNAMOELECTRIC MACHINES William Richards Holmes, New York, N. Y., assignor to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Application October 10, 1945, Serial No. 621,515

7 Claims.

The present invention relates to automatic control systems for dynamo electric machines and more particularly to systems for controlling automatically the connection of a plurality of such sources of current in parallel and for regulating said sources and maintaining the load properly divided between the sources after they are connected in parallel.

An object of the invention is to provide a novel system of control for a plurality of sources of current whereby the voltage of the sources of current may be maintained at a substantially constant value including means for momentarily decreasing the voltage setting of the connected sources and increasing the voltage setting of the disconnected sources prior to connection of the same into the load, and said means being arranged so as to effect a predetermined load division between the respective sources by balancing the settings of the respective sources.

Another object of the invention is to provide a novel relay arrangement for controlling the connection of each source of electrical energy to the load, in which the connection of each source to the load is dependent iirst upon the voltage of the source having a predetermined value and second upon the voltage of the source exceeding that of the load by a predetermined differential.

Another object of the invention is to provide a novel arrangement for varying the datum or voltage setting of the voltage regulating means, including novel relay means for connecting the datum changing means of the regulator of a given source of electrical energy in and out of operative relation, dependent upon the operating condition of the source of electrical energy in relation to the load.

Another object of the invention is to provide a novel means for disconnecting the means for maintaining a predetermined division of load between the sources of electrical energy out of operative relation with a given source, upon failure of said source, so as to thereby automatically protect the system against being adversely affected by the failure of the source.

Another object of the invention is to provide temperature responsive means for varying the generator load in accordance with the operating temperature of the generator.

These and other objects of the invention are pointed out in the following description in terms of the embodiment thereof which is shown in the accompanying drawings. It is to be understood, however, that the drawings are for the purpose of illustration only, and are not designed 2 as a definition of the limits of the invention. Reference being had to the appended claims for this purpose.

Referring to the drawing:

Figure 1 is a diagrammatic view of a system embodying the present invention in which a single control relay and regulator are shown in detail, like control relays and regulators being provided for each generator;

Figure 2 is a diagrammatic view of a second form of the invention and illustrating the operation thereof.

Referring to the drawing, numeral I indicates a generator of conventional type including an armature and commutator 2, shunt iield winding 3, and interpole compensating winding 4.

The generator l has suitable terminals A, B, D and E. The terminal A is connected through a suitable conductor 5 to the shunt field winding 3 while the opposite end of the shunt leld winding 3 is connected through a conductor 6 to negative output brushes on the commutator 2 suitably interconnected by a conductor 1. The commutator 2 has also provided positive output brushes suitably interconnected by a conductor 8. The conductor 8 is connected by a conductor 9 to the positive output generator terminal B, while the conductor l is connected by a conductor l0 to the negative output generator terminal D. The interpole compensating winding 4 previously noted is connected between the negative conductor 'l and the generator terminal E.

Leading from the positive output terminal B of the generator I is a conductor l! which leads to a terminal I2 on a regulator I3 and terminal I4 on relay control I5. There also leads from the negative output terminal D of the generator l a conductor I6 which is connected to regulator terminal Il and relay control terminal I8.

Leading from the interpole compensating winding terminal E of the generator l is a conductor IS which leads to a negative bus line 2U. A positive bus line 2l is connected through a main control relay switch 22 to the positive output terminal B by a conductor 23. The relay switch 22 is controlled by an electromagnetic winding 24 having one end connected through a ground connection 24A to the negative bus line 2D. The opposite end of the winding 24 is connected by a conductor 25 to a terminal 26 of the relay control l5. There further leads from the negative bus line 2D a conductor 2l which connects the negative bus line 20 to a regulator terminal 28 and a control relay terminal 29.

Connected across the control relay terminals I4 and 2t or the positive and negative terminals B and E respectively of the generator i is a voltage coil 3E] and a voltage coil 3| which are connected in parallel to the terminal Hi through a conductor 32 and to the terminal 29 through conductors 33 and 3d and a rectifier 35.

The voltage coil Sil controls spring tensioned switch arms 35 and 35A. The switch arms 36 and 36A close upon energization of the winding 3E) by a generator Voltage in excess of -a predetermined value. The switch arm 3@ closes a circuit from conductor t2 throughY a conductor 3l to a differential winding 3S.

The differential winding t8 has one end connected to a relay control terminal; 39 while the opposite end is connected to a controlA contact lit of the switch se. The terminalv 39 is connected.

hrough a conductor il tothe positive bus line Across the positive and negative bus lines. 2d and 2l there is connected a battery or load @2 havingv its negative terminal connected..` to the negativebus lineY 2o andits positive terminal con;r nected to the positive bus line 2 l.

The coils 3i and 35i-are arranged soas toconn trolthe closing of relay sp'ring'tensioned, switch arm 43 which controls a normally openl switch contact 5. The Contact i5 is connected to: the terminal 26, while' the switch arm d3 opens and closes Contact 55. The switcharm [i3 is connected byconducto-r sito conductor Si and through conm ductors 32e and: tl' to the positive terminal Bv of the generator l. Thus upon switch arm telosing contact 15, the electromagnet 2t isienergized closing switch 22 and connectingV the generator lto the bus linesZiand 2 i'.

The coil 35) sconnected across the output terminals B andI E of generatorA l' and registersr'the direct Voltage of generator' l and is arranged. to

close switch arms 3o and 3EAV at some predeter minedvalue below the normal voltage ofv bus lines 2li-and 2i, at for example 26 or 27 volts and opens ata-predeterminedvalue-below the normal voltagelof the battery d2, at for example 22 to 23 volts. l The coil Si isA likewise connected across the output terminalsB and E of the generator iv and registers the voltage of generator l. The coil 3| is yarrangedso as not to close relay switch arm A3 below apredetermined voltage, of for example 32ftof 34 volts, which voltage iss-o selected as to always be above the voltage of the bus lines 29A andZ-t.

The coil S8 is arranged so as to interconnect the positive terminals of the battery 42 and generator iY upon the closing of switch 35 so as to register the difference in voltage between the generator t and battert7 The coilV 38 is so arranged that whenrthe generator voltage exceedsthat of the'battery d2 or bus lines 2e and' 2l by apredetermined value, or above for example a 0.5 voltage differential, the current flow through coil- Et willbe lin a direction causing the magnetic force of the diierential coil Se to bey added tothe magnetic force ci voltage coil Si to cause switch arm i3 toclose contact @5.

As long asthe voltage of battery ft2 or the voltage of the bus` lines 2t. and 2l exceeds that of the generator l, the switch 133 will not close, since the current'low through coil 38 will be in an opposite direction to that previously described and will tend Yto counteract'the electromagnetic force of `the coil Si. When the'switch 22 closes it in effect shunts diierential coil 38 out of operation.

There` is further provided a current coil d8 for controlling the operation'of they switch arm i3 jointly'with the dierential coil 38 upon the clos- CTI ing of switch 36. One end of coil i8 is connected to terminal i8 while the opposite end is connected to terminal se. Thus, the coil i8 is connected across the interpole winding through conductors I and ii), and conductors 2, 20 and i9.

The winding it is so wound that should the voltage of generator l decrease to a value below that of the bus lines 253 and 2l so. that there is a reverse flow of current from the bus lines to the generator, then the magnetic ux of the voltage coil Si will be such as to decrease the total magnetic iorceV applied to switch arm @3, causing the same to open under the spring force of the switch arm d3. Upon switch arm i3 opening con- :Ytacte5, the electromagnet 2d is de-energized whereupon switch 22 under spring force disconnects the generator from the bus lines Eo and 2i.

The generator i' is controlled by a voltage regulator i3', including a variable resistance carbon pile element 5e connected at one end by an electrical conductor 5l to terminal l2 and through theconductor il tothe positive output terminal B of the generator i. The opposite end of the variable resistance element 5) is connected by conductor 52 to a. terminal 53 ci the regulator i3. A conductor iid leads from the terminal 53 tothe terminalA of the generator l and thereby to the eld winding 3 of the generator l.

Thus the carbon pile iilY regulates the excitation of the eld winding 3 of the generator l. The

suitable electromagnetic windings arrangedV so as to control an armature 5?' and .thereby thefpressure applied. to the carbon pile 5% and the. resistance thereof.

The regulator is shown diagrammatically in the drawing as including the armature 51 pivoted.

at Se and exerting a compressive torce upon the carbon pile 553' under tension of the spring 5S;

The spring 5SY is arranged so as to balance the electromagnetic force appliedA on the armature 59 by an electromagnetic winding til when energized by a voltage having a predetermined value and' is preferably of a type such asshown in the.

patent application SerialNo. 570;()02 of William G. Neild iiled December 27, 1944', now Ui Sl Patent No. 2,427,805.

The coil E@ is connected at one end by a conductor 5l to the terminal 28 and through conductors 2i, 20 and I9 to the terminal E of generator I. The opposite end of the winding 59T is connected by a conductor E32 to a terminali 63V which in turn is connected by a conductor @il to the positive output terminal B of theV generator l-,

Thus thecoil t@ responds to output voltage or" the generator l and is arranged 4to regulate the carbonpile E@ so as to control the excitation of the field winding 3 of the generator to maintain a predetermined generator output voltage.

A second electromagnetic winding 65l isY provided for Varying the datum or voltage setting oithe winding to. The' winding o5 has one end connected by a conductor 66 to a terminal 6T which is connected by a conductor 58 to a terminal S9 of the control relay i5.

The terminal e9' is connected by a conductor 'it to theV spring switch arm 35A controlled' bythe electromagnetic winding 3Q. The switch arm een is arranged to close aA contact 56A upon the vvoltage of the generator i reaching the predetermined value. The contact WA is connected lby conductoril to a terminal 'i l which is in turn connected by a conductor 'i2 to a manually'operable switch i3. The switch l'Scontrols a contact'v it. connected by conductor 'l5V to an equalizer` bus j line I6 for a purpose which will be explained. The switch arm 36A may if desired be controlled by a separate relay indicative of a predetermined generator voltage.

The other end of the compensating coil B5 is connected by a conductor I1 to an arm 18 of a potentiometer and contacting the potentiometer coil 'I9 at a point intermediate the opposite ends thereof. The opposite ends of the potentiometer coil 'I9 are connected to terminals I I and 28, respectively, which in turn connect the potentiometer coil I9 across the interpole compensating winding 4 through conductors I6 and 21, respectively.

The aforenoted arrangement is described and claimed in divisional application Serial No. 155,437, led April 12, 1950.

A plurality of generators I; IA; IB and IC are provided. Each of the generators IA; EB and IC has a, regulator similar to the regulator I 3 of the generator I and indicated herein as I3A; ISB and I3C respectively. Likewise the generators IA; IB; and IC have control relays similar to the control relay I5 of the generator I and indicated herein as I 5A; I5B; and I5C, respectively. For simplicity of illustration, the control and regulator circuit for the generator I only has been shown and the corresponding connections for the control and regulator circuits of the generators IA; IB; and IC have been indicated by like numerals bearing a letter A; B; or C corresponding to the respective generator to which the same relates.

Through the arrangement of the potentiometer 'IS across the interpole compensating winding 4, the coil 55 connected thereto through conductor 'II is responsive to the voltage drop across the winding 4 so as to decrease or increase the voltage setting of the regulator I3 dependent upon the relative outputs of the several generators.

The coil 65 is further connected to a similar coil in each of the regulators I3A; I3B and I3C through the equalizer bus and conductors 68A; 68B; and 68C and conductors 'I5A; 15B; and 15C and their respective relay controls I5A; I5B; and I5C, respectively.

The winding in each of the respective regulators I3A; ISB; and I3C corresponding to the winding 65 in regulator I3 is so designed that upon the generator controlled thereby assuming a greater portion of the load than the other generators the voltage drop across the winding 4 of the rst mentioned generator will exceed the voltage drop across the winding 1I of the several other generators, whereupon a current will flow in the coil 55 of the regulator for the iirst mentioned generator in a direction causing an increase in the magnetic force acting upon the armature 5l and increasing the resistance of the carbon pile 5G so as to reduce the voltage produced by the generator controlled thereby. This action will be readily apparent from Figure 2.

The direction of current flow through the compensating coil 65 of the other generators, however, will be in such a direction as to counteract the electromagnetic force of the main control winding BI) so as to cause the spring 59 to draw the armature 5'! in a direction for decreasing the resistance of the carbon pile 5I] and thereby increase the voltage produced by the generators controlled by the same until the generators are in a balanced relation.

The voltage coils 69 of the regulators I3; I3A; I3B; and I3C of the generators I; IA; IB; and IC are so calibrated as to regulate their respective generators so as to maintain substantially the same voltage, while the corresponding relays I5; I5A; I5B; and I5C are arranged to connect their respective generators into the bus lines 20 and 2| when their corresponding generators exceed that of the bus lines 20 and 2| by the predetermined diierential previously explained.

Thus, the generator rst reaching the predetermined differential above that of the battery or bus will be connected into the same.

When any other remaining generator has a voltage sufficient to close the equalizer circuit through switch 36A, the unbalance in voltages tends to decrease the voltage of the first generator and increase the voltage of the second generator due to the fact that the rst generator is connected to the load so as to produce a voltage across the interpole compensating winding, while the second generator which is not connected to the load through the switch 22 has a negligible voltage across its interpole compensating winding so that the current flow in the equalizer circuit is such as to decrease the voltage of the rst generator and increase the voltage setting of the regulator for the second generator. Thus, upon the voltage generator increasing to a value above the bus voltage by a predetermined differential, the second generator is connected to the load.

The other generators are connected into the load in a similar manner.

During operation of the generators should one tend to overheat the interpole compensating winding may be so designed as to increase its resistance with increase in generator temperature and thereby cause an increase in the voltage drop across the interpole compensating winding 4 causing in turn a ow of current in the equalizer circuit in a direction tending to increase the resistance of the carbon pile 50 and thereby produce a division of load by the several generators so that the generator which is overheated assumes a smaller portion of the load than the remaining generators.

Upon any one of the generators experiencing a decrease in voltage below that or" the bus or battery so that there is a reverse iow of current towards the generator, the latter generator` will be disconnected from the busor battery by the action of the reverse current coil 48 which is connected across the interpole compensating winding. Upon arm 43 opening the contact 45 the line switch coil 24 is de-energized causing line switch 22 to open.

Upon opening of line switch 22 there is a negative differential voltage impressed upon coil 38 which tends to cause a further decrease in the pull upon contact arm 43 so as to insure the maintenance of the same in open position.

In Figure 2, there is shown a somewhat modied form of the invention in which there is provided an external resistor 4A in place of the interpole compensating winding 4 previously described. Like numerals on Figure 2 indicate corresponding parts to those previously described with reference to Figure l and the interconnection of the compensating windings S5 for the generators I and I A are shown in greater detail.

The control relay for generator IA has been omitted for purposesl of clarity and its operation will be readily understood when considered with the explanation of Figure l.

Although only two embodiments of the invention have been illustrated and described, various changes in the form and relative arrangements 7" of the parts, which will now appear toV those skilled in the art, maybe made without departing from the scope of the invention. Reference is, therefore, to be had to the appended claims for a dennition of the limits of the invention.

What is claimed is:

1. A device for controlling the connection of a. generator to a load circuit, comprising, in combination, a first switch'member for causing the connection of said generator to saidl load circuit uponY the closure thereof, operating means for said first switchr member including a rst electromagnetic winding adaptedl to be energized by the* generator voltage, a second electromagnetic winthng adapted to be energized by the difference between the generator and load current conditions, a second switch member, operating means'for said second switch member including a third electromagnetic winding adapted to be energized by the generator Voltage, said second switch member controlling the circuit to said second electromagnetic winding and arranged to close said last mentioned circuit upon a generator voltage in excess'of a predetermined value, said second electromagnetic winding arrangedv so as to act accumulatively with respect to said nrst electromagnetic winding so as to close said nrst switch member' upon said generator current predominating, said nrst switch member controlling the circuit to said second electromagnetic winding and arranged so as to shunt said second electromagnetic winding upon actuation to Va closed position, a fourth electromagnetic winding adaptedv to be energized by the current 'ow through said load circuit and arranged so as to tend to maintain said nrst switch member in a closed position while said generator current predominates and to effect the opening of said first switch member upon saidl load current predominating so as to dis'N connect said generator from the load circuit, another generator connected' to said' load circuit, a regulator for each of the generators for maintaining a predetermined generator ,voltage output, said regulators including means for eiecting a predeterminedV division of load between the generators, a-third switch member for confnecting said load dividing means into operation, and third electromagnetic winding arranged to operate said third switch member in response to the output voltage of said rst mentioned generator.

2. A device for controlling the connection of a generator to a load circuit, comprising, in combination, a nrst switch member for causing the connection of said generator to said load circuit upon the closure thereof, operating means for said iirst switch member including a first electromagnetic winding adapted to be energized by the generator Voltage, a second electromagnetic winding adapted to be energized by the difference between the generator and load current con-A ditions, a second switch member, operating means for said second switch member including a third electromagnetic winding adapted to be energized by the generator voltage, said second switch member controlling the circuit to said second electromagnetic winding and arranged to close said last mentioned circuit upon a generator voltage in excess of a predetermined value, said second electromagnetic winding arranged so as to act accumulatively with respect to said first electromagnetic winding so as to close said nrst switch member upon said generator current predominating, said rstswitch member control- 8 ling the circuit to said second electromagnetic winding and arranged so as) to shunt said second electromagnetic winding upon actuation to a closed position, a fourth electromagnetic winding adapted to be energized by the current flow through said load circuit and arranged so as to tend to maintain said first switch member in a` closed position while said generator current predominates and to effect the opening of said nrst switch member upon said load current predominating so as to disconnect said generator from the load circuit, a plurality of other generators connected to said load circuit, a regulator for each of the generators for maintaining a predetermined generator voltage output, each of said regulators including means for eiecting a predetermined division of load between the generators, a circuit for interconnecting said load dividing means, a third switch member for opening and closing said circuit to the load dividing means of the first mentioned generator, and said third switch member actuated to a closed position by said third electromagnetic winding upon the output voltage of said first mentioned generator exceeding a predetermined value.

3. In combination, a load circuit, a plurality of generators' for said load circuit, a regulator associated with each of said generators, electric circuit means interconnecting the regulators of each of said generators so as to maintain a predetermined division of load between the generators, each of said generators having associated therewith a resistorV in the load circuit, said resistor arranged so that the resistance thereof may vary in accordance with the operating temperature of its associated generator, and said electric circuit means including a voltage dividing means connected across each of said resistors and responsive to change in the fall of potential across any one of said resistors for varying the division of load in accordance with the relative operating temperatures of the respective generators so as to avoid the overheating thereof.

4. In combination, a load circuit, a' plurality of generators for saidload circuit, a regulator associated with each of said generators, electric circuit means interconnecting the regulators of each of said generators so as to maintain a predetermined division of load between the generators, each of said regulators having associated therewith a resistor in the load circuit, said electric circuit means including a voltage dividing means connected across each of said resistors and responsive to change in the fall of potential across any one of said resistors for adjusting said regulators so as to maintain a predetermined division of load between said generators, and relay7 means associated with at least one regulator for disconnecting the regulator from said interconnecting circuit upon the output Voltage of the generator associated with the regulator decreasing below a predetermined value.

5 In combination, a load circuit, a plurality of generators for said load circuit, a regulator associated with each of said generators, electric circuit means interconnecting the regulators of each of said generators so as to maintain a predetermined division of load between the generators, relay means associated with at least one generator for connecting said generator into the load circuit upon the generated current of said generator exceeding the load current by a predetermined value, saidfregulators arranged so as to maintain a predetermined generator voltage,

means for varying the voltage setting of each regulator so as to decrease the voltage setting of the regulator of the generator connected to the load circuit and increase the voltage setting of the regulator for said one generator when disconnected from the load circuit so that the relay means associated with the last mentioned generator may eiect the connection thereof to the load circuit upon the generated current of the last mentioned generator exceeding the load current by the predetermined value.

6. In combination, a load circuit, a plurality of generators for said load circuit, a regulator associated with each of said generators, electric circuit means interconnecting the regulators of each of said generators so as to maintain a predetermined division of load between the generators, relay means associated with at least one generator for connecting said generator into the load circuit upon the generated current of said generator exceeding the load current by a predetermined value, said regulators arranged so as to maintain a predetermined generator voltage, means for varying the voltage setting of each regulator so as to decrease the voltage setting of the regulator of the generator connected to the load circuit and increase the voltage setting or" the regulator for said one generator when disconnected from the load circuit so that the relay means associated with the last mentioned generator may effect the connection thereof to the load circuit upon the generated current of the last mentioned generator exceeding the load current by the predetermined value, and said voltage varying means arranged so as to maintain a predetermined division of load between said generators when connected to the load circuit.

7. In combination, a load circuit, a plurality of generators for said load circuit, a regulator associated with each of said generators, electric circuit means interconnecting the regulators of each 10 of said generators so as to maintain a predetermined division of load between the generators, relay means associated with each generator for connecting said generators into the load circuit upon the generated current exceeding the load current by a predetermined value, said regulators arranged so as to maintain a predetermined generator voltage, means for varying the voltage setting of each regulator so as to decrease the voltage setting of the regulators of those generators connected to the load circuit and increase the voltage setting of the regulators for those generators disconnected from the load circuit so that the relay means associated with the last mentioned generators may affect the connection thereof to the load circuit upon the generated current of the last mentioned generators exceeding the load current by the predetermined value, said Voltage varying means arranged so as to maintain a predetermined division of load between those generators connected to the load circuit, and means including electromagnetic windings responsive to the voltages of the associated generators for disconnecting said voltage setting varying means from any one of said regulators upon the voltage produced by the associated generator decreasing below a predetermined minimum value.

WILLIAM RICHARDS HOLMES.

REFERENCES CITED The following references are of record in the ille of this patent:

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